Mesomorphic Properties of 4-n-Pentylbiphenyl Derivatives

Abstract

In this work, 29 compounds having the general formula:

were prepared and their electron spectra, phase transition temperatures and mesomorphic properties determined. Compounds with Z=H, Br, I, NH₂, CN, CHO, NCS, NCO, N₃, COOH, CH₂COOH, CH₂Br, CH₂CN, COCH₃, CH₂‒CH₂Cl, CH₂‒CH₂CN, CH₂CHClCN, CH^˭CH₂ , C≡CH, CH≡CHCN, C(CH₃)˭NOH, CH˭NOH, C(CH₃)=NOC₂H₅, C₅H₁₁, C₆H₁₃, C₇H₁₅, COC₄H₉, COC₅H₁₁, COC₆H₁₃ were investigated. On the basis of compounds of formula 1, differing only by the kind of the terminal substituent Z, the effects of geometry, coupling, direction and magnitude of the dipole moment on their mesomorphic properties are discussed. These relationships suggest that the nematogenic properties of biphenyl derivatives depend chiefly on the ability of the molecules to associate linearly.